BUMO ATP 20 Protocol · Documentation

Overview

ATP 20 (Account based Tokenization Protocol) provides protocol standards for issuing tokens based on BUMO contracts. ATP 20 also provides interfaces for third parties to transfer and use tokens.

Purpose

Based on this standard interface, tokens can be quickly docked and used by other applications and third parties, such as wallets and exchanges.

Rule

BUMO smart contracts are implemented by JavaScript language, including initialization function init and two entry functions, main and query. The init function is used to initialize contract creation; the main function is mainly responsible for data writing, the query function is responsible for data querying.

Attributes of Tokens

The attributes of tokens are stored in the smart contract account, and you can check them by using the tokenInfo function. The attributes of tokens are as follows:

Variable	Description
name	Token name
symbol	Token symbol
decimals	Decimal places of tokens
totalSupply	Total amount of tokens (*The value is 10 ^ decimals issuing amount**)
version	ATP version

Attention:

name：Full spelled words with initial letters capitalized are recommanded, such as Demo Token.
symbol：Capitalization and acronyms are recommended, such as DT.
decimals：The number of decimal places which is in the range of 0~8, and 0 means no decimal place.
totalSupply：The value is in the range of 1 ~ (2 ^ 63 - 1). For example, when issuing 10000 tokens with 8 decimal places, the value of totalSupply is 1000000000000 (10 ^ 8 * 10000).
version：The version of ATP, Such as ATP20.

Event

The functions transfer, transferFrom , approve will trigger the event (see the description of each function for details), The event is to call the tlog function, and a transaction log is recorded on the blockchain. The log records the function call details for the user to read.

The tlog is defined as follows:

tlog(topic,args...);

tlog: It will generate a transaction written on the block.
topic: Log subject, must be a string type, parameter length (0,128].
args...: It can contain up to 5 parameters, and the parameter type can be string, numeric or Boolean type, each parameter length (0,1024].

Functions

The functions provided in BUMO ATP 20 Protocol include transfer, transferFrom, approve, balanceOf, tokenInfo, and allowance.

transfer

Function

It is used to transfer (value) tokens to the destination address (to), and the log event must be triggered. An exception will be thrown if the source account does not have enough tokens.
Entry function

main

The parameters are in json format

{
    "method":"transfer",
    "params":{
        "to":"buQnTmK9iBFHyG2oLce7vcejPQ1g5xLVycsj",
        "value":"1000000"
    }
}

The json parameters

Parameter Description

to The address of the destination account.

value The amount of tokens allowed to be transferred (string).
Function call
```
function transfer(to, value);
```
Return value

Returning true or throw an exception.
event：
```
tlog('transfer', sender, to, value);
```
topic: The function name, here is 'transfer'.

sender: The account address to call the contract.

to: The address of the destination account.

value: The amount of tokens allowed to be transferred (string).

Parameter	Description
to	The address of the destination account.
value	The amount of tokens allowed to be transferred (string).

approve

Function

Authorized account spender can transfer value token from the transaction sender account.
Entry function

main

Parameters are in json format.

{
    "method":"approve",
    "params":{
        "spender":"buQnTmK9iBFHyG2oLce7vcejPQ1g5xLVycsj",
        "value":"1000000"
    }
}

The json parameters

Parameter Description

spender The account address of the spender.

value The amount of tokens an account is authorized to transfer (string).
Function call
```
function approve(spender, value)
```
Return value

Returning true or throw an exception.
Event：
```
tlog('approve', sender, spender, value);
```
topic: The function name，here is 'approve'.

sender: The account address to call the contract.

spender: The account address of the spender.

value: The amount of tokens an account is authorized to transfer (string).

Parameter	Description
spender	The account address of the spender.
value	The amount of tokens an account is authorized to transfer (string).

transferFrom

Function

It is used to transfer (value) tokens from the source address (from) to the destination address (to), and the log event must be triggered. Before the transferFrom function is called, the source address (from) must have authorized the destination address (to) by calling the approve function for transferring a certain amount of tokens. If the amount of tokens in the source address (from) is insufficient or if the source address (from) has not authorized the destination address (to) for transferring enough amount of tokens, then the transferFrom function will throw an exception.
Entry function

main

The parameters are in json format

{
    "method":"transferFrom",
    "params":{
        "from":"buQnTmK9iBFHyG2oLce7vcejPQ1g5xLVycsj",
        "to":"buQYH2VeL87svMuj2TdhgmoH9wSmcqrfBner",
        "value":"1000000"
    }
}

The json parameters

Parameter Description

from The source address.

to The destination address.

value The amount of tokens allowed to be transferred (string).
Function call
```
function transferFrom(from,to,value)
```
Return value

Returning true or throw an exception.
Event：
```
tlog('transferFrom', sender, from, to, value);
```
topic: Function name, here is transferFrom.

sender: The acount address to call the contract.

from: The source address.

to: The destination address.

value: The amount of tokens allowed to be transferred (string).

Parameter	Description
from	The source address.
to	The destination address.
value	The amount of tokens allowed to be transferred (string).

balanceOf

Function

It is used to check the balance of the owner account.
Entry function

query

The parameters are in json format

{
  "method":"balanceOf",
  "params":{
      "address":"buQnTmK9iBFHyG2oLce7vcejPQ1g5xLVycsj"
  }
}

The json parameters

Parameter Description

address Account address
Function call
```
function balanceOf(owner)
```

Parameter	Description
address	Account address

Return value

The balance of specified address, such as follows:

{
  "result":{
      "balanceOf":"100000000000000",
  }
}

tokenInfo

Function

It is used to get the basic information of the token.
Entry function

query
The parameters are in json format
```
{
  "method":"tokenInfo"
}
```
Function call
```
function tokenInfo()
```

Return value

  {
    "result":{
        "type": "string",
        "value": {
            "tokenInfo": {
                "name": "DemoToken",
                "symbol": "DT",
                "decimals": 8,
                "totalSupply": "5000000000000",
                "version": "1.0"
            }
        }
    }
  }

allowance

Function

It is used to check the amount of tokens still allowed to be transferred from the token owner.
Entry function

query

The parameters are in json format

{
  "method":"allowance",
  "params":{
      "owner":"buQnTmK9iBFHyG2oLce7vcejPQ1g5xLVycsj",
      "spender":"buQYH2VeL87svMuj2TdhgmoH9wSmcqrfBner"
  }
}

The json parameters

Parameter Description

owner The account address of the token owner.

spender The account address of the spender.
Function call

function allowance(owner, spender)

Parameter	Description
owner	The account address of the token owner.
spender	The account address of the spender.

Return value

  {
    "result":{
        "allowance":"1000000",
    }
  }

Contract Entry Function

init

When the contract is created, the contract init entry function is triggered, which is responsible for the initialization of the contract creation
Function call
```
function init(input_str){
}
```

Parameters are in json format

{
    "params":{
        "name":"DemoToken",
        "symbol":"DT",
        "decimals":8,
        "totalSupply":"5000000000000",
        "version": "1.0"
    }
}

Return value

Return true or throw an exception.

main

It is used for data writing, which includes the transfer, transferFrom and approve functions.

Function body

function main(input_str){
    let input = JSON.parse(input_str);

    if(input.method === 'transfer'){
        transfer(input.params.to, input.params.value);
    }
    else if(input.method === 'transferFrom'){
        transferFrom(input.params.from, input.params.to, input.params.value);
    }
    else if(input.method === 'approve'){
        approve(input.params.spender, input.params.value);
    }
    else{
        throw '<Main interface passes an invalid operation type>';
    }
}

query

It is used for data querying, which includes the tokenInfo, allowance functions.

Function body

function query(input_str){
    globalAttribute = JSON.parse(storageLoad(globalAttributeKey));

    let result = {};
    let input  = JSON.parse(input_str);

    if(input.method === 'tokenInfo'){
        result.tokenInfo = globalAttribute;
    }
    else if(input.method === 'allowance'){
        result.allowance = allowance(input.params.owner, input.params.spender);
    }
    else{
        throw '<Query interface passes an invalid operation type>';
    }
    return JSON.stringify(result);
}